The present invention relates to a method as well as to an apparatus for transmitting a continuous data stream in packetized form using a storage device in which the data can be temporarily stored for specific times before and after their transmission.
Such a method and such an apparatus are required, for example but in no way exclusively, in radio systems operating by using the DECT Standard.
However, considerable complexity is required in order to make it possible to ensure that there are no errors in the data transmission.
It is accordingly an object of the invention to provide a method and an apparatus for transmitting a continuous data stream in packetized form, which overcome the hereinafore-mentioned disadvantages of the heretofore-known methods and apparatuses of this general type in such a way that the complexity which must be accepted in order to be able to ensure that a data transmission is free of errors is kept at as low a level as possible.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method for transmitting a continuous data stream in packetized form using a storage device for temporarily storing the data for specific times before and after transmission of the data, which comprises temporarily storing data of data packets in a cyclic buffer; and temporarily storing addresses, starting with which the data are stored in the cyclic buffer, in read-pointer temporary storage devices.
In accordance with another mode of the invention, there is provided a method which comprises reading the data to be transmitted from the cyclic buffer immediately before transmission of the data, and preparing the data for transmission together with signaling and error protection data in a transmission buffer.
In accordance with a further mode of the invention, data packets which are not transmitted without any errors are transmitted once again.
In accordance with an added mode of the invention, there is provided a method which comprises supplying a start address, from which the data to be transmitted can be read from the cyclic buffer, from a read-pointer temporary storage device, at least when the data are transmitted once again.
With the objects of the invention in view there is also provided an apparatus for transmitting a continuous data stream in packetized form, comprising a storage device for temporarily storing data in data packets for specific times before and after transmission of the data, the storage device being or containing a cyclic buffer; and a multiplicity of read-pointer temporary storage devices for storing addresses starting with which the data stored in the cyclic buffer are stored.
The replacement of the FIFO storage which is normally used for temporary storage with a cyclic buffer makes it possible to dispense with the provision of transmission repetition temporary storage devices. In contrast to the situation with FIFO storage devices, the data which may need to be transmitted once again may be read at any desired times and as often as desired from any desired points within the cyclic buffer.
Apart from this, the operation of the cyclic buffer is simpler and less problematic than that of a FIFO storage device. Specifically, in contrast to the situation in which a FIFO storage device is used, the use of a cyclic buffer means that it is unnecessary to shift or store the stored data once again continuously internally. As a result, the cyclic buffer has been found to be the considerably better variant both in terms of power consumption and in terms of temperature response.
It is thus possible, by using the method according to the invention and the apparatus according to the invention, to reduce to a minimum the complexity which has to be accepted in order to be able to ensure that the data transmission is free of errors.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method and an apparatus for transmitting a continuous data stream in packetized form, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.